SDA and SDL for the WD65c02s its for epprom

[DerpymanMT]

Im new to the world of 6502, and I cant find a EEPROM that had more pins than just sda and sdl, I cant really get any more different chips, Because im pretty sure the WD65s02c cant handle more than 64k of memory... (please correct me if im wrong) my EEPROM chip that i am getting, is 8k and i am getting a 16k sram chip, but enough of that, tell me if i need any more chips before i place the order... OR Tell me how to attach it to the mpu...
Thank you

[Dr Jefyll]

Welcome to our 6502 world, DerpymanMT

DerpymanMT wrote:

tell me if i need any more chips before i place the order...

CPU, RAM and EPROM are the main ones. But you'll need some sort of Input-Output -- such as a UART, perhaps (to provide serial communications with a terminal or a host computer). You'll also need a clock source and some sort of (preferably simple) address decode circuit. BTW, you don't need an EEPROM, since the EPROM can provide much the same function.

Quote:

OR Tell me how to attach it to the mpu...

You can find the info you need in Garth's excellent primer, written specifically for people doing what you are doing.

Have fun, and keep us posted!

Jeff

[Chromatix]

EEPROMs with parallel interfaces (essentially the same pinout as the same size EPROM or SRAM) do exist, are inexpensive, and are much easier to boot a 6502 system from than a serial EEPROM.

You can sensibly boot from a small parallel EEPROM and then load further data from a larger serial EEPROM, which you might implement a filesystem on.

[floobydust]

As already noted, the W65C02 uses an 8-bit parallel data bus and a 16-bit address bus, so 64KB (65,536 bytes) is the native range and I/O also needs to be mapped as part of that space.

With the current pricing of SRAM and EEPROM, I'd suggest you just pick up a 32KB SRAM (Alliance AS6C62256-55PCN) and a 32KB EEPROM (Atmel 28C256) , plus a few logic chips, like a 74HC00, 74HC30 and 74HC138, along with a clock oscillator, a DS1813 reset chip and some caps, switches, sockets, etc. And of course some sort of I/O device so you can talk to it (UART is fine, but be careful using the W65C51 as the latest WDC part has problems).

This will allow you to build something reasonable and simple up front that you can actually work with. In addition to Garth's primer (should be considered required reading), I'd also suggest looking at Daryl Rictor's older SBC 2.5 shown here: http://sbc.rictor.org/sch2.html

This will give you a more flexible system once you breadboard something from Garth's primer. Finally, you might find Ben Eater's recent 6502 video interesting: https://eater.net/6502

Good luck on your new venture

[drogon]

DerpymanMT wrote:

Im new to the world of 6502, and I cant find a EEPROM that had more pins than just sda and sdl, I cant really get any more different chips, Because im pretty sure the WD65s02c cant handle more than 64k of memory... (please correct me if im wrong) my EEPROM chip that i am getting, is 8k and i am getting a 16k sram chip, but enough of that, tell me if i need any more chips before i place the order... OR Tell me how to attach it to the mpu...
Thank you

Do you mean SDA/SDL or SDA/SCL? If it were SCL then I'd be thinking that you're looking at I2C eeproms. You need a parallel type eeprom for a 65C02 system.

Garth's 6502 primer is listed above, but also running right now as a series of YouTube tutorials and web blogs and Ben Eaters 6502 system - it lists all the parts you need to get a basic system going. https://eater.net/6502

-Gordon

[Martin A]

I usually use NOR flash rather than EEPROM on new builds. The Microchip SST39SF0x0 range is both cheaper and faster than the Atmel 28C256.

On a first project the speed might not be important but it does give more time for the chip select logic etc.

The down side is they’re all 32 pin parts and not 28 so potentially awkward on a legacy board.

When, using one in the place of a smaller capacity part just connect the extra address lines to 0v

[DerpymanMT]

I will check the primer and, but I also have to say I have a very limited budget of around 60 dollars.. so the cheaper it is the more likely I will buy it unless it is very essential, but I will add these chips to my shopping list on mouser! Thank you for your help! I will try to find parallel EEPROMs or make a UART system for my computer.